Oh, and it all works nice with FireSass: “A new :debug_info option has been added that emits line-number and filename information to the CSS file in a browser-readable format. This can be used with the new FireSass Firebug extension to report the Sass filename and line number for generated CSS files.”

@AngusC: This is not a new client-side language. I gets compiled to regular css. Take a look at their website, it might surprise you how easy it all works, I’m thinking about using this for my next project.
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PS: I do think it’s a bit user-unfriendly to expect your users to be proficient in css to change their interface…

It looks just as bad as normal sass. No idea why people like it, apart from being able to declare variables, but that can be done in normal CSS syntax if you make for yourself tool to “compile” it to working CSS.